LaunchBar has this functionality, and I use it extensively.
To be honest, I don't use it for pictures, so I don't know how they handle it, but it handles text beautifully.
And the launch key is a double CMD/C (that's hold command and press C twice). Which is intuitive, because it is the same key combination. And next time you just do a normal CMD/C (once) for a normal copy, then we start again.
And what's more, there's clipboard history, so if you forget to double C, you haven't lost anything. And even more… I believe the shortcut access and paste options for the clipboard history is the best I have come across (and I have tried many utilities).
And, (finally), you get the benefits of LaunchBar's main asset as a launcher, which I've become so used to it, I can't live without it.